A brain-machine interface (BMI) or a brain-computer interface (BCI) is a direct communication pathway between a brain and an external device. BMIs can be used to assist, augment and/or repair human cognitive or sensory-motor functions. In one example, a BMI can include an array of electrodes that are invasively or partially invasively spread over an area of a subject's brain. The array of electrodes can obtain neural signal information from the subject's brain. The neural signal information can be communicated to the external device for analysis.
Electrocorticography (ECoG), or intracranial electroencephalography (iEEG), is a practice of using electrodes placed directly on an exposed surface of a brain in order to measure electrical potentials (or electrical activity) from the brain's cerebral cortex. The electrodes can be referred to as an intracranial electrode grid. Since a surgical incision into the skull is performed to implant the intracranial electrode grid over the brain, ECoG involves an invasive surgical procedure. In one example, electrical measurements from the ECoG can be used to identify epileptogenic zones (i.e., regions of the brain that generate epileptic seizures), which can be subsequently removed during surgery.
ECoG is growing in importance for brain-machine interfaces (BMI), and is a fundamental research tool for the investigation of long-range neural circuitry and synchronization. For BMI applications, the development of large area, high-resolution ECoG electrode grids is desirable. Although ECoG recordings have been found useful for epilepsy monitoring and for effectively controlling cursor movements at the brain-machine interface (BMI), traditional ECoG recordings are occasionally complicated by hemorrhage, infection, infarction, etc.
Traditional ECoG electrode grids can include a polydimethylsiloxane (PDMS) sheet with embedded platinum studs connected to a recording apparatus. These traditional ECoG grids can suffer from several disadvantages such that continued improvements in ECoG grids are desirable.